All across the interwebz!
http://tweetsonbeats.com
http://twitter.com/TweetsOnBeats
http://www.facebook.com/pages/Tweets-On-Beats/111667718908211
http://tweetsonbeats.tumblr.com/
Submit your beats! Make 1 bar intro and then 8 more bars of beats. Make sure to fill in the right BPM and add your @twitter handle as a track tag.